Evason included a picture of his TweetDeck app, spattered with dozens of other users' account icons, and went on to demonstrate his ability to tweet from another user's account.

Twitter immediately took down the Web version of TweetDeck and posted the following tweet: "TweetDeck is currently down while we look into an issue. Apologies for the inconvenience."

The company declined to comment further.

TweetDeck, which was acquired by Twitter in May 2011, is available as both a Web and desktop application. Many users reported that their Web application was offline, and some said that their desktop version was also down. Other users, especially those on older versions of TweetDeck's desktop client, appeared to be unaffected by the shutdown.

It's the latest bug to hit the rapidly growing social network.

The company recently acknowledged a software flaw that makes it look as though users are not "following" people they actually are -- a problem that has caused much confusion and frustration among Twitter's power users. Twitter noted the problem and said its engineers were working to resolve it.

Twitter is no stranger to glitches. In 2010, the company experienced growing pains as it worked to strengthen its infrastructure and roll out new features. Members became intimately familiar with the iconic "Fail Whale."

But as the company's profile grows, its margin for error is dwindling. Twitter now claims more than 100 million active users and fields more than 250 million tweets a day.

As one Twitter employee recently told CNNMoney: "It's not cute anymore if Twitter doesn't work. There's a lot more on the line."